IJASCSE, Vol 2, Issue 1, 2013 www.ijascse.in Page 15 Feb. 28 Design Equation for CFRP strengthened Cold Formed Steel Channel Column Sections Sreedhar Kalavagun ta , Sivakumar Naganathan, and Kamal Nasharuddin Bin Mustapha Universiti Tenaga Nasional, Jalan IKRAM-UNITEN, 43000, Department of Civil Engineering, Kajang, Selangor, Malaysia. Abstract — Carbon fibe r re inforce po lym e r (CF RP) strengthene d ste el structural me mb ers such as beam s, columns and bridge de cks have becom e p rogres sive ly pop ular as a res ult of exte nsive stud ie s in this fie ld. This pape r prese nts the re cent de ve lopments in CF RP strengthe ned ste e l channel se ctions and propose d conceptual model for prediction of column strength unde r pure axial loads pe r I ndian stand ards-I S80 1-197 5 and Euro code 3(EC 3)standards . Eight cold-formed steel circular lipped channel section columns with exte rnally b onde d CF RP we re te ste d unde r pure axial com press ion. I S801/EC3 propose d m et hods w e re com pared with expe ri m ental res ults. The res ults s how that the p roposed m ethod gi ve s around 11 percent increas e in stre ngth d ue to CF RP. Keywords- CF RP streng the ning, I S80 1, Cold form e d Ste e l , Axial Compression. I. I NTRODU CTI ON Cold formed steel sections gained special attention in research due to its major advantages like flexibility in drawing up any shape, high ratio of strength to weight, light in weight, easy to transport and erect, recycle etc. Cold formed steel sections with edge stiffened flanges have three types of buckling like local buckling, distortional buckling, and Euler's buckling (flexural or flexural-torsional) generally called as global buckling, has been investigated by a number of researchers[1,2,3,4,5,6,7,8,9,10]. In recent years, the use of carbon fiber-reinforced polymer (CFRP) materials for repair strengthening and repair in columns has been widely utilized as a result of design code revision, environmental deterioration, physical aging, and catastrophic events. Advantages of CFRP over other conventional repair materials include its higher strength to-weight ratio, additional corrosion resistance, very low coefficient of thermal expansion, and ease of application. Past two decades there are two major strengthening techniques have been widely applied, including CFRP plate bonding and column wrapping. In recent years, there has been a trend towards using this technique to repair and strengthen steel members with CFRP[11,12,13], particula rly in the fi eld of thin-walled ste el structure s. CFRP wrapping method is an economical and easy-to-implement retrofitting method to Increase the axial compression. Increase shear strength Increase the flexural rigidity Increase the durability Increase seismic resistance etc,. Most recently research on the strengthening on circular steel sections with CFRP, Jimmy Haedir et al., studied on axial compression and flexural and posed design equation for steel tubular sections[14,15,16,17], M. Elchalakani et al., on plastic mechanism [18], Nuno Silvestre et al., [19, 20] studied on non-linear behavior and load carrying capacity of CFRP- strengthened lipped channel steel columns. II. MATERIALS AND METHODS A Total of 8 CFRP strengthened cold formed channel sections and plain cold formed sections were tested. Each specimen was cut to final length, ranging from 500 mm to